The Prince and Princess of Wales landed in the United States on Wednesday to begin their four-day visit to Boston, culminating in the Earthshot Prize Awards on Friday. Along with her many sustainable outfits for her several upcoming engagements over the next few days, there is also one outfit the princess must always bring with her in her Royal Tour suitcase: an all-black ensemble.
Royal tours - and wardrobes - take a bucket-load of organisation, especially when you’re one of the most photographed members of the Royal Family.
Kate, 40, has become known for being able to walk the line between getting the dress code right, respecting the host nation and remaining approachable, so we can only imagine the forward planning that goes into a tour wardrobe with several public events, both formal and informal.
On top of that, there's also an stipulation in place for when a royal travels abroad - and the reason is fairly sombre.
When any member of the Royal Family travels to another country, they must always pack an all-black outfit.
The reason being in case they have to attend a last-minute funeral in the host nation, or someone in the family were to pass away whilst they were abroad. For the latter, the unusual rule ensures that when they arrive back in the UK, they are dressed appropriately to match the sombre mood of the nation.
The unusual sartorial stipulation is now a compulsory rule that all members of the Royal Family must adhere to, but it wasn’t always the case.
Elizabeth was on a trip to Kenya with Prince Philip when they heard the news that her father King George VI had died at home in the UK, and as such, the then-Princess would become Queen.
The late monarch had failed to pack anything black for her trip to Africa, and knew that she couldn’t arrive in the country wearing unsuitable attire, as her plane was sure to be greeted by dozens of photographers desperate to get a glimpse of the new Queen.
So, Elizabeth ended up having to wait on the plane once it landed so that an aide could fetch her a more appropriate black ensemble for her to wear before she disembarked in front of the world’s press.
Since then, the Queen made it clear that everyone should be prepared for the worst at a moment’s notice, even when on a family holiday, but especially whilst on a royal tour.
Watch: Billie Eilish and Ellie Goulding lead musical line-up for Prince of Wales' Earthshot Prize ceremony